GUCA2B and irritable bowel syndrome: Using Pearson's test, uroguanylin immunoreactive cells density before FMT correlated positively with diarrhea (r = 0.97, P = 0.001) and negatively with bloating (r = −0.91, P = 0.01) in the PI-IBS subgroup (Figures 5(a) and 5(b), respectively).